Smoke eliminators



May 21, 1957 J. H. FORREST SMOKE ELIMINATORS Filed Dec. 12, 1955 INVENTOR JOHN H. FORREST ATTORNEY United States Patent SMOKE ELIMINATORS John H. Forrest, Hope, British Columbia, Canada pp ic on D em e 12, .1 Se ia No- 5 2,

2 Claims. (Cl. 183-926) My invention relates to improvements in smoke eliminators.

The object of the invention is to provide a simple device in which the solids in suspension in flue gases may be effectively removed, and at a relatively low cost.

A further object is to effect the desired washing of the smoke with but little Water, so that the residue may be reduced to a semi-solid if desired for removal to a point of subsequent treatment, or for the recovery of any values it may contain.

A further object is to take advantage of direction changes and deceleration of the gas flow in the device to enhance the removal of solids from the smoke.

Referring to the accompanying drawings:

Figure l is a partly cross sectional view of the invention.

Figure 2 is a plan view, taken on the line 22 of Figure 1.

Figure 3 is a fractional vertical sectional view showing the approximate water level in the stack when the device is in operation.

In the drawings like characters of reference indicate corresponding parts in each figure.

The numeral 1 indicates a receiver, conical in form and having a discharge outlet 2 at its apex which connects With a drain pipe 3. The receiver 1 is carried by legs 5 which extend upwardly beyond said receiver to support an extractor structure 7 which consists of an inner vertical cylinder 8 having a frusto conical bell 9 at its lower end. Surrounding the cylinder 8 is an outer cylindrical column 11 having a frusto conical base 12, the walls of which extend substantially parallel to those of the bell 9, so that the velocity of down flow gases in the cylindrical column 11 will be materially reduced as they fiow downwardly between the frusto conical base 12 and the bell 9.

The base 12 is provided with a shallow dished bottom wall 14 having a concentric discharge opening 16 which is below the normal water line N. L. in the receiver 1. A pipe 17 communicating with a source of smoke or other gas to be cleaned, connects with the cylindrical column 11. An inclined top plate 19 encloses the upper end of the column 11 and a substantially dome shaped chamber 20 is formed upon said plate. The upper end of the vertical cylinder 8 communicates with the chamber 20 through the plate 19 and an outlet pipe 22, of the same cross sectional area as that of the smoke pipe 1'7, extends from said chamber 21) to the inlet side of a suction fan 24. The cross sectional area of the chamber 20 is considerably greater than that of the vertical cylinder 8.

Extending downwardly from the lower part of the chamber 20 is a waste pipe 26 which is adapted to discharge into the receiver 1. A water jet 28 is directed into the receiver at an acute angle to a radius of said receiver and at a point somewhat below its normal water level N. L., as shown in Figure 1. This jet is supplied with water from a supply pipe 29 and is automatically controlled by any appropriate means by a valve 39.

An overflow weir 32 is provided in the receiver 1, which is adapted to discharge surplus water through a 2,792,905 Patented M y 7 drain 33 ShOwn in Figure 2 only. This weir functions in conjunction with the automatically controlled valve 30 and serves to maintain the water level N. L. or the running level indicated in Figure 3 as R. L.

The operation of the device is as follows: Water is admitted to the receiver 1 and is brought up to the level indicated as N. L. of Figure l. Thesuction fan 24 is set in motion to develop a predetermined velocity in the pipes 17 and 22 and to take away the smoke to be treated as fast as it develops. The smoke on entering the vertical column 11 decreases its velocity according to the increase in cross sectional area of said vertical column over that of the pipe 17. As the smoke descends through the annulus surrounding the hell 9 its velocity is still further reduced somewhat. During the descent of smoke and its suspended solids, the particles in the solids will by virtue of their gravity travel almost vertically downwards and will largely resist the suction of the gas as its direction is changed on entering the vertical cylinder 8, so that a large proportion of said particles will be caused to plunge into the water on the surface of the dished bottom wall 14. The suction on the gas in the vertical cylinder 8 will be such as to set up a turbulence in the water within said dished bottom wall, breaking its surface into little wavelets in more or less ring formation, so that fines or minute particles entrained in the air or gas are caused to plunge into said wavelets and be precipitated therein. The action of the gas across the water surface and the wavelets breaks said Water into a state of high division which serves to entrap and impregnate the solids when being drawn upwardly through the cylinder 8 and into the head 20. The impregnated solids on being carried into the head 20 are changed from traveling in a vertical direction towards a horizontal one and on account of their increase of weight due to water absorption and the decrease of velocity due to the increased cross sectional area of the head over that of the vertical cylinder 8, said solids fall rapidly onto the inclined plate out of the gas stream and are conveyed through the waste pipe 26 back to the receiver 1. The water entering the receiver from the jet 28 creates a circular flow around the conical side walls of said receiver, thereby causing the solids to gradually flow downwardly towards the outlet 2 and the swirling motion within the receiver will also exert a similar but lesser rotating motion within the dished bottom wall 14, which enables the sludge to work its way downwards through the opening 16 into the receiver. The water level in the base 12 and the velocity of the suction applied to the device are maintained at a constant during all running times, so that the air gap between the lower edge of the bell 9 and the water level R. L. will remain narrow enough to materially increase the substantially horizontal gas flow velocity and thus maintain a high degree of separation of solids from the gas or smoke treated.

What I claim as my invention is:

1. A smoke eliminator comprising a vertical cylinder forming an upcast column, a cylindrical column surrounding said vertical cylinder and forming a down cast column, said down cast column having a smoke inlet on one side and a dished bottom wall, a receiver into which the bottom wall of the down cast column is adapted to extend, means for maintaining a predetermined water level in the receiver, said bottom wall having an opening communicating with the receiver whereby water from the receiver will flow into the bottom wall, said down cast column having a top closure, said upcast column having a head of greater cross sectional area than the upcast column and an outlet pipe from said head adapted for connection to the suction side of an exhaust fan and a pipe for draining moisture laden solids from within the head and means for sealing the pipe against air ingress from below, said receiver being in the form of a cone and being placed concentrically to the opening in the bottom wall, said means for'maintaining the water level being a jet extending through a wallof the receiver, said jet being disposed at an angle to a radius of said receiver and adapted to create a rotational flow in' the receiver and above the bottom wall at thetbase of the cylindrical column.

2; A smoke eliminator comprising a vertical cylinder forming an upcast column and having a frusto conical bell at its lower end, a cylindrical column surrounding said vertical cylinder and forming a down cast column, said cylindrical column having a smoke inlet on one side and a frusto conical base, said base having a dished bottom well, said bottom wall enclosing the frusto conical bell and said bell being spaced above the bottom wall to form a circular gap, a receiver into which the bottom wall is adapted to extend, means for maintaining a predetermined water level in the receiver, said bottom wall having an opening communicating with the receiver and being adapted to be normally covered with water from the receiver whereby gas flowing from the down cast column to the upcast column must flow across the surface of the water as it flows through the circular gap, said down cast column having a top closure, said upcast column having a head of greater cross sectional area than the upcast column, an outlet pipe from said head adapted for connection to the suction side of an exhaust fan, a pipe for draining moisture laden solids from within the head, and means for sealing the pipe against air ingress from below.

References Cited in the file of this patent UNITED STATES PATENTS Uri. 

